javascript数组到二维数组

Question

i have a javascript array like this

var myArr = [  

   {  
      "Year":"2015",
      "Month":"January",
      "Value":"15.8",
      "District":"Anuradhapura",
      "type":"Rainfall"
   },
   {  
      "Year":"2015",
      "Month":"January",
      "Value":"31.1",
      "District":"Anuradhapura",
      "type":"Temparature"
   },
   {  
      "Year":"2015",
      "Month":"January",
      "Value":"4",
      "District":"Anuradhapura",
      "type":"Wind"
   },
   {  
      "Year":"2015",
      "Month":"January",
      "Value":"69",
      "District":"Anuradhapura",
      "type":"Humidity"
   }
]

what i need is to put type and Value data into 2 dimension array. my end result should be like this;

 var data = [  
       [  
          "Rainfall",
          158
       ],
       [  
          "Temparature",
          31.1
       ],
       [  
          "Wind",
          4
       ],
       [  
          "Humidity",
          69
       ]
    ]

note that myArr results i'm getting from the backend service and the length of this array can be change dynamically. how can i do this. thanks

Answer 1

Try this:

With foreach function

Documentation: Array.forEach

var data = [];

myArr.forEach(x => data.push([x.type, parseFloat(x.Value)]))

With map function

Documentation: Array.Map

var data = myArr.map(x => [x.type, parseFloat(x.Value)] );

Answer 2

You can simply use Array.map function to map object array to two dimensional array.

  var data = myArr.map(function(o){
       return [o.type, o.Value]
    });

Also if you want value to be converted into a float number instead of string , do this with pasreFloat

  var data = myArr.map(function(o){
       return [o.type, pasreFloat(o.Value)]
    });

Answer 3

You can use Arrays.map function to get the result:

     var data = myArr.map(function(input){ return [input.type, input.Value]; });

This function will transform each element of your array into another element, because you need an array of arrays, your mapping function must create an array out of an object.

Answer 4

let data = [];
myArr.map( a => {

 data.push([a.type, a.Value]);

});

Answer 5

I am familiar with underscore.js: you may use:

_.zip(_.pluck(myArr, "type"), _.pluck(myArr, "Value"));

 var myArr = [ { "Year":"2015", "Month":"January", "Value":"15.8", "District":"Anuradhapura", "type":"Rainfall" }, { "Year":"2015", "Month":"January", "Value":"31.1", "District":"Anuradhapura", "type":"Temparature" }, { "Year":"2015", "Month":"January", "Value":"4", "District":"Anuradhapura", "type":"Wind" }, { "Year":"2015", "Month":"January", "Value":"69", "District":"Anuradhapura", "type":"Humidity" } ]; alert(JSON.stringify(_.zip(_.pluck(myArr, "type"), _.pluck(myArr, "Value")))); 

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